Pfizer reports promising findings for RSV vaccine in at-risk adults 18 to 59 years old

News brief

Pfizer today announced promising phase 3 clinical trial findings for a single dose of its respiratory syncytial virus (RSV) vaccine, Abrysvo, in adults ages 18 to 59 who are at increased risk of RSV infection and signaled that it would submit data to regulatory agencies as part of application for approval in that age-group.

woman immunized

In May 2023, the Food and Drug Administration (FDA) approved Abrysvo for use in adults ages 60 and older, and the Centers for Disease Control and Prevention (CDC) recommended its use in that age-group, based on shared decision making with health providers. In September 2023, the CDC recommended the vaccine for pregnant women as part of a strategy to protect vulnerable newborns.

Good safety, immune response

Pfizer said the new phase 3 findings are from a trial that examined safety and immunogenicity on adults ages 18 to 59 who are at risk for severe RSV infection such as those with asthma and diabetes. Currently, no RSV vaccines have been approved for this age-group.

Neutralizing responses against RSV-A and RSV-B were noninferior to those earlier trials in adults ages 60 and older. The younger adults had at least a fourfold increase in serum neutralizing titers 1 month following vaccination. The vaccine was well tolerated and had safety findings similar to trials in other populations. 

Pfizer said it will publish the findings in a peer-reviewed medical journal and present them at an upcoming medical conference.

WHO warns about rising viral hepatitis deaths

News brief

Global deaths from viral hepatitis are rising, despite progress with prevention and better tools for diagnosis and treatment, the World Health Organization (WHO) warned today in its annual hepatitis report, which it released at the World Hepatitis Summit.

hepatitis B
NIAID/Flickr cc

New data show that deaths rose from 1.1 million in 2019 to 1.3 million in 2022. Hepatitis is the second-leading infectious disease cause of death, with levels about the same as tuberculosis, another leading cause of infectious disease fatalities.

Of hepatitis deaths, 83% were due to hepatitis B, with 17% related to hepatitis C. The WHO estimates that 3,500 people die each day from their hepatitis B or C infections.

The WHO said half of the disease burden is in adults ages 30 to 54, with men accounting for 58% of cases.

Also, disease burden varies by region, with 10 countries making up nearly two thirds of global viral hepatitis cases: Bangladesh, China, Ethiopia, India, Indonesia, Nigeria, Pakistan, the Philippines, Russia, and Vietnam.

Challenges include treatment access, service delivery

Though affordable generic treatments are available, many countries haven't procured them, and problems with access are made worse by pricing disparities and centralized service delivery, the WHO said.

The agency said achieving the elimination goal by 2030 is still possible, and it detailed several steps for accelerating the process, including streamlining service delivery and mobilizing innovative financing.

WHO is committed to supporting countries to use all the tools at their disposal.

In a statement, WHO Director-General Tedros Adhanom Ghebreyesus, PhD, said, "WHO is committed to supporting countries to use all the tools at their disposal—at access prices—to save lives and turn this trend around."

PAHO issues alert about drug-resistant Campylobacter cases

News brief

The Pan American Health Organization (PAHO) last week urged member states to be on alert for cases of antibiotic-resistant Campylobacter infection in men who have sex with men (MSM) and outbreaks in high-risk populations.

Citing a February outbreak of drug-resistant Campylobacter in 13 MSM in Minnesota, as well as and multiple small outbreaks in MSM in Canada dating back to 1999, PAHO encouraged member states in an information note to be vigilant in cases of MSM presenting with diarrhea with dysentery features. 

Maintaining vigilance

"While reporting of Campylobacter outbreaks in MSM in the Americas is not alarmingly frequent at present, the cases were associated with a high rate of antimicrobial resistance," PAHO said. "Therefore, Member States are encouraged to maintain surveillance for outbreaks of diarrhea, particularly in MSM populations."

Although Campylobacter is most commonly known as a foodborne bacterial pathogen that causes diarrhea, it is among the species of enteric pathogens that is also known to be transmitted among MSM through oral and anal sex and is frequently associated with resistance to commonly used antibiotics. PAHO recommended providing counseling to MSM on the risks of transmitting enteric pathogens during sexual activity and when to seek treatment for dysentery symptoms.

The note also urged member states to be on the lookout for unusual increases in Campylobacter infections in high-risk populations such as people ages 65 and older, pregnant women, and people with weakened immune systems. 

While reporting of Campylobacter outbreaks in MSM in the Americas is not alarmingly frequent at present, the cases were associated with a high rate of antimicrobial resistance.

Surveys spotlight pregnant women's drop in confidence over COVID vaccines

News brief
Marina Demidiuk / iStock


A new study details dramatically lower confidence in COVID-19 vaccine safety in pregnant and recently pregnant women in 2023 compared to 2021, despite evidence to the contrary, according to findings published yesterday in JAMA Network Open.

The study was based on responses given in two survey waves from 2021 to 2023, with 1,227 total respondents. Wave 1 took place from October 2021 to February 2022, and wave 2 took place from November 2022 to February 2023

Participants, members of the Vaccine Safety Datalink (VSD), were asked about their vaccination status, race, ethnicity, and preferred language, as well as whether they somewhat or strongly agree with the statement that COVID-19 vaccines are safe. 

77% had at least one vaccine dose

Overall, 76.8% (95% confidence interval [CI], 71.5% to 82.2%) reported one or more COVID-19 vaccinations. All participants identified as female, and the average age was 31.7 years. A total of 356 (29.0%) identified as Black race, 555 (45.2%) identified as Hispanic ethnicity, and 445 (36.3%) preferred the Spanish language. 

Spanish-speaking Hispanic women had the highest self-reported rate of any COVID-19 vaccination, 86.9% (95% CI, 82.0% to 91.8%) in wave 1, and 84.2% (95% CI, 80.4% to 88.1%) in wave 2.

The weighted estimates of somewhat or strongly agreeing that COVID-19 vaccines are safe decreased from wave 1 to 2 for respondents who reported having received at least one vaccine dose (76% in wave 1 compared to 50% in wave 2). Among non-Hispanic White respondents, the drop was from 72% to 43%; Spanish-speaking Hispanic respondents went from 76% vs 53%.

These differences, despite accruing evidence of COVID-19 vaccine safety in this high-risk group, are concerning for clinicians and public health officials.

"The general trends we observed among those who had received at least 1 COVID-19 vaccine and among racially, ethnically, and linguistically diverse groups are concerning," the authors said. "These differences, despite accruing evidence of COVID-19 vaccine safety in this high-risk group, are concerning for clinicians and public health officials."



This week's top reads